Question: $\begin{aligned}&\phantom{{\times}}9\\ \\ &\underline{\times0}\\ \\ \end{aligned}$ $~~$
We can think of ${9} \times {0}$ as $9$ groups of $0$ circles: $\text{Group 1}$ $\text{Group 2}$ $\text{Group 3}$ $\text{Group 4}$ $\text{Group 5}$ $\text{Group 6}$ $\text{Group 7}$ $\text{Group 8}$ $\text{Group 9}$ Since there are $0$ circles in each group, the answer is $0$. $\begin{aligned}&\phantom{{\times}}9\\ \\ &\underline{\times0}\\ \\ &\phantom{{\times}}0 \end{aligned}$